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  1. #1
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    -ve square wave using a dc voltage

    Hi,

    Is it possible to get a square wave with both 40v +ve & 40v -ve sides, using a 40vdc and a 5v squarewave ?

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    Re: -ve square wave using a dc voltage

    Hi,

    There is a lot of information missing.
    A picture could help.

    Your question is: "is it possible.."
    My anser is: YES.

    using a 40vdc and a 5v squarewave ?
    I assume you mean a sinlge 40V DC power supply (0V, +40V)
    --> use a DPDT relay with 5V coil voltage:
    * one NC1 to 40V, the NO1 from the same contact to 0V
    * other contact NO2 to 40V, NC2 to 0V
    * coil connected to GND and 5V square wave.
    * output: COM1 and COM2

    Connect a scope or DVM to COM1 abd COM2 and see +/-40 square wave.
    ****
    Similar solutions can be made using an DPDT analog switch (faster, low power)
    Or with a MOSFET power full bridge (fast, high power)
    ...and maybe hundreds of other solutions....depending on your (missing) specifications.

    Klaus



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    Re: -ve square wave using a dc voltage

    I want to test this circuit but I have only 40volt supply.
    I need both positive and negative voltage at the output.




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    Re: -ve square wave using a dc voltage

    Hi,

    If you need both positve and negative output you need both positve and negative supply.

    But I doubt the 741 is specified to work with +/- 40V supply.

    * I wonder why you talk about 5V square wave... This has nothing to do with the shown circuit.

    ***
    Please give complete and detailed informations .. not piece by piece.

    Klaus



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    Re: -ve square wave using a dc voltage

    Not sure exactly what you need, but you can create a negative rail from a positive DC supply. See this video https://youtu.be/LtoPHevexTM



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    Re: -ve square wave using a dc voltage

    The video in post #5 is informative. It discusses a charge pump. The same concept is used in this simulation, where you get -38V by drawing power from a +40V supply.



    For the clock signal, you can make that your 5V square wave. It can drive a low side NPN. Then add another NPN in such a way as to drive the high side PNP on/ off.

    If you were to decide that a bipolar +-20V supply is suitable, then it would be convenient and efficient to split your +40V supply.



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  7. #7
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    Re: -ve square wave using a dc voltage

    sure, use a transformer with the output center tapped. connect 40V to center tap, and put 5V square wave on primary



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